Ch. 10 Muscle Tissue

Question 1

What are the 6 functions of skeletal MUSCLES?

Answer 1

1. Produce skeletal movement
2. Maintain posture & body position
3. Support soft tissues (abdominal wall and floor of pelvic cavity)
4. Guard entrances and exits
5. Maintain body temperature
6. Store nutrient reserves

Question 2

What are the three layers of muscle?

Answer 2

1. epimysium
2. perimysium
3. endomysium

Question 3

What are the components of skeletal muscle?

Answer 3

1. muscle tissue (cells or ‘fibers’)
2. connective tissue
3. nerves
4. blood vessels

Question 4

A dense layer of collagen fibers that surround the entire muscle. Separates the muscle from nearby tissues and organs.

Connected to deep fascia, a dense connective tissue layer.

Answer 4

Epimysium

Question 5

• Divides the skeletal muscle into a series of compartments; surrounds muscle fiber bundles
• Contains blood vessels and nerve supply to fascicles

Answer 5

Perimysium

Question 6

A bundle of muscle fibers surrounded by the perimysium

Answer 6

fascicle

Question 7

• Surrounds individual muscle cells (muscle fibers)
• Contains capillaries and nerve fibers contacting muscle cells
• Contains myosattelite cells (stem cells) that repair damage

Answer 7

Endomysium

Question 8

a bundle at the end of each muscle that usually attaches it to bones

Answer 8

tendon

Question 9

a broad sheet at the end of muscle tissue that usually attaches it to bone

Answer 9

aponeurosis

Question 10

a group of embryonic cells that fuse and form individual multinucleate skeletal muscle fibers.

Answer 10

myoblast

Question 11

Where does each nucleus in multinucleate muscle cells originate?

Answer 11

myoblasts

Question 12

Where do myosattelite cells come from?

Answer 12

Myoblasts that did not fuse with developing muscle fibers

Question 13

the plasma membrane of muscle fiber

Answer 13

sarcolemma

Question 14

cytoplasm of a muscle fiber

Answer 14

sarcoplasm

Question 15

Why is sarcoplasm different from other plasma membranes?

Answer 15

It has a membrane potential due to the unequal distribution of positive and negative charges

Question 16

• Transmit action potential through cell
• Allow simultaneous contraction
• Same properties as sacolemma

Answer 16

Transverse tubules

(T tubules)

Question 17

• Lengthwise subdivisions within muscle fibers
• Made up of bundles of protein filaments
• Actively shorten. Responsible for muscle contraction
• 100s - 1,000s per fiber

Answer 17

myofibrils

Question 18

protein bundles that make up myofibrils. Two types.

Answer 18

myofilaments

(thin and thick)

Question 19

composed of actin

Answer 19

thin filaments

(myofilaments that make up myofibrils)

Question 20

composed of myosin

Answer 20

thick filaments

(myofilaments that make up myofibrils)

Question 21

Provide energy (ATP) for short-duration, maximum intensity muscular contractions

Answer 21

glycolysis

mitochondria and granules of glycogen scattered among the myofibrils of each muscle fiber

Question 22

– A membranous structure surrounding each myofibril

– Helps transmit action potential to myofibril

– Similar in structure to smooth endoplasmic reticulum

– Forms chambers (terminal cisternae) attached to T tubules

Answer 22

sarcoplasmic reticulum

Question 23

• Chambers next to T-tubules where the SR enlarges, fuses and forms expanded chambers
• Concentrate Ca2+ (via ion pumps)
• Release Ca2+ into sarcomeres to begin muscle contraction

Answer 23

terminal cisternae

Question 24

formed by one T tubule and two terminal cisternae

Answer 24

Triad

Question 25

protein in terminal cisternae that reversibly binds Ca²⁺

Answer 25

calsequestrin

Question 26

* The contractile units of muscle * Structural units of myofibrils * Form a striated pattern within myofibrils * Alternating dark, thick filaments (A bands) and light, thin filaments (I bands)

Answer 26

Sarcomeres

Question 27

What are the four components of sarcomeres?

Answer 27

1. thick filaments 2. thin filaments 3. proteins that stabilize filament positions 4. proteins to regulate interactions between filaments

Question 28

acronym for thin and thick bands

Answer 28

th **_I_** n filaments look l **_I_** ght and form the ***I*** bands **A** bands are d**A**rk

Question 29

Three components A Band

Answer 29

**1. M line** **2. The H Band** **3. Zone of overlap**

Question 30

– The densest, darkest area on a light micrograph – Where thick and thin filaments overlap - Where triads surrounding sarcomeres are located; calcium ions released here

Answer 30

Zone of overlap

Question 31

The H Band

Answer 31

## Footnote – The area around the M line – Has thick filaments but no thin filaments

Question 32

M line

Answer 32

– The center of the A band – At midline of sarcomere

Question 33

Zone of overlap

Answer 33

– The densest, darkest area on a light micrograph – Where thick and thin filaments overlap - Where triads surrounding sarcomeres are located; calcium ions released here

Question 34

## Footnote – The area around the M line – Has thick filaments but no thin filaments

Answer 34

The H Band

Question 35

– The center of the A band – At midline of sarcomere

Answer 35

M line

Question 37

contains thin but not thick filaments

Answer 37

The I band

Question 38

Marks the boundary between adjacent sarcomeres

Answer 38

Z lines